The techniques of endodontia are becoming more important to students learning the art of dentistry. In recent years great progress has been made in endodontia and because of it, dentists are frequently able to preserve teeth even after they have become abscessed, that is, after the root canal of the tooth becomes infected. To preserve an abscessed tooth, the dentist or endodontist must carefully and completely remove the nerve structure and pulp before filling the root cavity with a filler material, such as gutta percha. If any vestige of the root canal or pulp material remains in a tooth, it is subject to becoming infected and, therefore, the careful cleaning and shaping of a root canal is a most critical part in any endodontic procedure. To provide a means for students to practice cleaning and shaping root canals, others have suggested the provision of root canal practice models. An early example of a device for use in practicing endodontia procedures is set forth in U.S. Pat. No. 3,947,967 entitled "Root Canal Model For Use In Practicing Dental Art Training". This patent teaches the formation of a block of transparent material having a cavity in it conforming to the typical shape of a root canal. The cavity can be filled with a material and the student can practice the art of cleaning the root canal. By making the block of transparent material, the student is able to observe the process as it is practiced and to visually determine when the artificial root canal has been thoroughly cleaned and shaped.
U.S. Pat. No. 4,137,633 entitled "Root Canal Practice Model" shows a variation of the basic root canal practice block by providing a plug of a resilient mass located at the root canal apex so that the student can determine tactically when a file has reached the root canal apex.